Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1343—Electrodes
  • G02F1/134309—Electrodes characterised by their geometrical arrangement
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
  • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/133504—Diffusing, scattering, diffracting elements
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1343—Electrodes
  • G02F1/134309—Electrodes characterised by their geometrical arrangement
  • G02F1/134318—Electrodes characterised by their geometrical arrangement having a patterned common electrode
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
  • G02F1/292—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection by controlled diffraction or phased-array beam steering
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
  • G03H1/2202—Reconstruction geometries or arrangements
  • G03H1/2205—Reconstruction geometries or arrangements using downstream optical component
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
  • G03H1/2294—Addressing the hologram to an active spatial light modulator
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F2203/00—Function characteristic
  • G02F2203/24—Function characteristic beam steering
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
  • G03H2001/0208—Individual components other than the hologram
  • G03H2001/0224—Active addressable light modulator, i.e. Spatial Light Modulator [SLM]
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
  • G03H2001/2605—Arrangement of the sub-holograms, e.g. partial overlapping
  • G03H2001/261—Arrangement of the sub-holograms, e.g. partial overlapping in optical contact
  • G03H2001/2615—Arrangement of the sub-holograms, e.g. partial overlapping in optical contact in physical contact, i.e. layered holograms
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
  • G03H2001/2625—Nature of the sub-holograms
  • G03H2001/264—One hologram being a HOE
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2225/00—Active addressable light modulator
  • G03H2225/10—Shape or geometry
  • G03H2225/11—1D SLM
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2225/00—Active addressable light modulator
  • G03H2225/20—Nature, e.g. e-beam addressed
  • G03H2225/23—Grating based SLM
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2225/00—Active addressable light modulator
  • G03H2225/55—Having optical element registered to each pixel
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2225/00—Active addressable light modulator
  • G03H2225/60—Multiple SLMs
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49117—Conductor or circuit manufacturing
  • Y10T29/49124—On flat or curved insulated base, e.g., printed circuit, etc.
  • Y10T29/49155—Manufacturing circuit on or in base

Definitions

• Light modulation device for a display for displaying two- and / or three-dimensional image contents
• the invention relates to a light modulation device for a display for displaying two- and / or three-dimensional image contents or image sequences.
• the light modulation device has a light modulator and a control device.
• the phase and / or the amplitude of a substantially collimated light wave field can be varied with the light modulator as a function of the location on the light modulator.
• the light modulator can be controlled by the control device.
• the present invention relates to a display and a method for producing a light modulation device.
• Holographic displays which contain a light modulator (Spatial Light Modulator, SLM) with a matrix-like arrangement of pixels.
• SLM Spatial Light Modulator
• These may, for example, be light modulators having the phase or amplitude or the phase and the amplitude - i. complex-valued - can change or modulate the light interacting with the SLM.
• an autostereo display according to WO 2005/060270 A1, in which the current eye position of at least one observer is detected and the stereoscopic images are deflected in the direction of the left and right eye of the observer depending on the current eye position become.
• a diffraction order In a Fourier plane of such a holographic display, higher diffraction orders are produced Diffraction orders are proportional to the reciprocal of the pixel pitch of the SLM of the display, ie the center-to-center spacing of the periodic light modulator structures
• a diffraction order For holographic displays with a viewing window, a diffraction order must be at least the size of that viewer window Since the viewer window usually only has to be slightly larger than the diameter of an eye pupil, this results in a relatively large pixel pitch of the SLM, a typical value being 30 ⁇ m to 50 ⁇ m.
• a holographic reconstruction is only visible when the viewer positions an eye on the viewer window. Either the viewer must therefore assume a fixed position or the observer window must follow the current eye position of the observer (tracking). For this purpose, a detection of the eye position and an arrangement for observer tracking are needed.
• Known arrangements for observer tracking such as the light source tracking described in WO 2006/119920 A1 or, for example, the electrowetting tracking described in WO 2008/142108 A1, are complicated in terms of design.
• Z-tracking ie the tracking of the observer window in the axial direction of the display (when moving the Viewer eyes to the display or when moving away the viewer eyes away from the display), for example, requires a variable field lens function.
• Coding tracking can be used meaningfully, but is also limited by the pitch of the SLM.
• the tracking area can have more than one during coding tracking
• the intensity of the tracked observer window would decrease according to the intensity in the higher diffraction orders. As a rule, this would make sense as an area for the observer tracking one or, at most, two to three
• an SLM with a smaller pixel pitch.
• a reasonable range of motion of a viewer in front of a holographic display includes an angle of a few degrees.
• a pitch in the range of a few micrometers would be required.
• a 24 inch display with a pitch of, for example, 2 ⁇ m would result in approximately 40 billion pixels, which would not be feasible in real time in terms of manufacturing, driving, and computing the hologram data.
• the present invention is therefore an object of the invention to provide a light modulation device, a display and a method for producing a light modulation device of the type mentioned and further, by which the aforementioned problems are overcome.
• an easy-to-implement tracking of the observer window of the holographic display or a tracking of the sweet spot of an autostereoscopic display or a beam deflection for multi-view displays should be specified.
• a light modulation device of the aforementioned type is characterized in that at least one diffraction device is arranged downstream of the light modulator in the propagation direction of the light wave field.
• the diffraction device has a variable diffraction structure. With the diffraction structure, the light wave field changed by the light modulator can be changed variably in a predeterminable manner.
• tracking of at least one observer window can be realized, in particular, by arranging a diffraction device, which has a variable diffraction structure, downstream of the light modulator in the propagation direction of the lightwave field.
• a diffraction device which has a variable diffraction structure, downstream of the light modulator in the propagation direction of the lightwave field.
• This can be used so that, depending on the current eye position of a viewer, the diffraction structure of the diffraction device is changed in such a way that the diffraction device generates prescribable higher diffraction orders of the light wave field influenced by the light modulator or the light rays in the direction of the current eye position of a viewer deflected by diffraction accordingly.
• periodic repetitions of the light wave field influenced by the light modulator arise.
• the diffraction structure of the diffraction device is to be set or controlled by a control device such that a repetition of the light wave field influenced by the light modulator or of the observer window also arises at the current eye position of a viewer of the display. In this way, the viewer can visually perceive the information inscribed in the light modulator according to the principles described in WO 2006/066919 A1.
• the diffraction structure of the diffraction device could have any periodic structure.
• a two-dimensional lattice structure is conceivable here.
• the diffraction structure of the diffraction device is preferably a one-dimensional lattice structure or a sawtooth structure.
• a substantially vertically extending one-dimensional linear lattice structure could be realized in the diffraction device to produce a diffracted in the horizontal direction periodic repetition or diffraction orders.
• the diffraction device is also suitable for changing the phase of the light wave field and thereby locally deflecting individual parts of the light wave field, the diffraction device could also be referred to as a phase deflector.
• a one-dimensional linear grating structure could be realized in the diffraction device, which has a predeterminable angle relative to the horizontal.
• the diffraction structure of the diffraction device should have a grating period or a periodic distance which is substantially of the order of the wavelength of the light used.
• the effect of the diffraction device is not exclusive of diffraction of the light passing through the diffraction device. Even when the grating periods are in a range of greater than, for example, 10 ⁇ m, the operation of the diffraction device is that of an element which changes the phase of the light. Accordingly, the diffraction device is also to be understood in this context in the following.
• two diffraction devices are provided, of which a diffraction device only realizes a vertical deflection and the further diffraction device only a horizontal deflection.
• These two diffraction devices are designed in analogy to a phase SLM as pixelated elements with a controllable phase modulation in many stages between 0 and about 2 ⁇ of the wavelength of light used, but so that there is only a strip-shaped or only columnar arrangement of pixels.
• a very fine structuring can be set in one dimension or direction (horizontal or vertical) so that a small pixel pitch (or a small grating period) can be realized for a large angle range of the observer tracking.
• the other dimension vertical or horizontal
• continuous pixels are present essentially over the entire height or width of the diffraction device (which can also realize the function of a phase deflector or a phased array).
• the pixel pitch in the finely-structured direction is chosen according to the wavelengths of illumination used and the angular range desired for those wavelengths.
• the terms horizontal and vertical in this context are to be understood in a generalized manner, in particular, as being two directions arranged approximately perpendicular to one another.
• the entire tracking arrangement could also be rotated, for example such that one tracking direction is + 45 degrees diagonally and the other tracking direction is - 45 degrees diagonally.
• phase light modulators can be used for diffraction devices.
• a diffraction device is described below, which is based on phase modulation by means of liquid crystals.
• the production and control of the diffraction device is advantageously much less complex than that which may be the case, for example, with liquid cells arranged in matrix form (an electrowetting cell array).
• a diffraction device for realizing horizontal diffraction would have only 265,000 pixels; a diffraction device for realizing a diffraction in the vertical direction only 150000 pixels.
• the number of pixels is smaller in this case than with a horizontally and vertically pixelated light modulator with VGA resolution.
• a binary grating with invariable diffraction structure - for example a polarization grating - has a largely invariable grating period and thus realizes a substantially invariable deflection angle.
• the variably controllable diffraction device by means of a multiplicity or a series of diffraction structures in the form of phase steps, which can be written into the diffraction device, by varying the quantization (ie the number) of the phase steps and / or the slope of the linear phase curves, the deflection or diffraction angle of the light passing through the diffraction device can be set variably in very fine steps / steps.
• phase values for the position of each pixel of the diffraction pattern are calculated modulo 2 ⁇ .
• the representable phase step (quantization) with the smallest difference to this calculated value is written into the respective pixel of the diffraction structure.
• the calculation modulo 2 ⁇ automatically ensures a continuous phase progression of the light wavefront.
• the calculation of the phase values for the diffraction device can also be considered in analogy to a blazed grating:
• Deflection angles are determined from the lateral nominal position of the observer window and its distance from the display in order to deflect light from a position on the display or light modulator towards the observer window.
• a blazed grating is calculated whose grating period corresponds to the desired deflection angle, according to the general grating equation:
• ⁇ is the angle of the incident light
• ⁇ is the angle of the light deflected by the grating
• m is the diffraction order.
• ⁇ is the wavelength of the light used
• g is the lattice constant of the blazed grating. The plus sign on the left side of the equation is applicable when the incident light beam and the diffracted light beam are on the same side of the entrance window. The reverse is true for the minus sign.
• This blazed grating is scanned with the sample points spaced from the pixel pitch of the diffraction device and the resulting samples written to the diffraction device. According to the sampling theorem, the blaze grating can be scanned correctly if the grating period g is at least twice the pixel pitch of the diffraction device.
• p denotes the pixel pitch of the diffraction device.
• any grating periods of the Blaze grating can be realized. Therefore, finely tunable adjustable deflection angles are possible (ie small tracking steps) up to a maximum angle which corresponds to the blazed grating with a grating period which is twice the pixel pitch of the diffraction device.
• Diffraction means would correspond to the use of grating periods of the blazed grating which are smaller than twice the pixel pitch of the diffraction device. Despite the violation of the scanning theorem, part of the light in a higher order of the diffraction device is directed to the desired position. In addition, however, a generally brighter repetition of the observer window also arises in the 0th order of the diffraction device. For a sufficiently small pitch of the diffraction device These orders are farther apart than the eye relief and would not disturb a single viewer.
• Suppression of higher orders is particularly necessary for a multi-viewer system when higher orders resulting from tracking a single viewer would disturb another viewer.
• a light modulator is combined with two separate diffraction devices.
• a hologram is encoded in the light modulator, the light modulator having a relatively coarse pixel pitch (e.g., 30 ⁇ m x 30 ⁇ m) and a horizontal / vertical matrix of pixels.
• the one diffraction device is provided for a horizontal and the other diffraction device is for a vertical observer tracking.
• Each of the two diffractive devices has a fine pitch (for example, 1 ⁇ m), but is patterned in only one dimension at a time. The range of motion of the observer is then about as large as would be conceived in a much more sophisticated system with a single light modulator with a pixel pitch of, for example, 1 ⁇ m x 1 ⁇ m and 160 billion pixels and with coding tracking.
• a field lens function could be variably controlled by taking into account corresponding phase terms and optionally priced terms at least partially in the diffraction device.
• the field lens function corresponds to a different deflection angle locally in different lateral positions on the display or the light modulator.
• no periodic structure would be inscribed here in the diffraction device, which has a substantially constant grating period over the entire effective area of the diffraction device.
• it is moreover intended to inscribe a grating structure or a diffraction structure over the entire effective area of the diffraction device, which has a variable grating period or diffraction structure over the entire effective area of the diffraction device, so that hereby a field lens function can be realized.
• the pixel pitch of the diffraction device must then be chosen so small that even the maximum deflection angle from the opposite Lichtmodulator- or display edge to the viewer is still within the diffraction order used.
• the display additionally has a field lens which can not be changed in its optical property.
• This field lens focuses on a mean observer distance and a median lateral observer position.
• This can optionally be realized refractive or diffractive, the latter, for example, by a correspondingly sized and arranged Bragg grating.
• the diffraction device in the beam path is preferably arranged after the Bragg grating, since this requires a fixed angle of incidence.
• the refractive lens may optionally be arranged before or after the diffraction device.
• a tracking of a viewer window in the direction along the optical axis or in a direction perpendicular to the surface of the light modulator could take place by writing additional lenses representing phase terms in the light modulator and / or in the at least one diffraction device.
• a compensation of aberrations of a field lens provided in the display could then take place in the at least one diffraction device and in the light modulator by coding. In this case, a larger pixel pitch of the diffraction device is sufficient for a specific tracking angle range than would be required if the entire field lens function were integrated in the diffraction device and the light modulator.
• a spherical lens function for example, the phase terms for the entire field lens or for the
• Additional lens for Z-tracking or an aberration correction may not be completely decomposed into independent horizontal and vertical phase courses.
• Lens function would vividly correspond to the difference between a single spherical lens and two crossed cylindrical lenses.
• the phase curves of the cylindrical lenses and the spherical lens would only coincide in the paraxial approximation, ie for a small aperture of the lenses. They differ for larger lenses. This means that the required horizontal phase curve on the display in order to deflect light to a specific observer position, for example at the top
• Edge of the display may be different than in the middle or below and that the required vertical
• Phase history for example, on the left side of the display can be different than in the middle or right.
• phase curve ⁇ (x, y) which represents the lens function or aberration correction is then advantageously decomposed in the following way:
• ⁇ ( ⁇ , y) q> i ( ⁇ ) + ⁇ 2 (y) + ⁇ 3 ( ⁇ , y)
• ⁇ - ⁇ (x) is a phase function which depends only on the horizontal coordinate
• q> 2 (y) a phase function which depends only on the vertical coordinate.
• the latter has an illumination device which has an optical waveguide, from which the light running in the optical waveguide is evanescently coupled out by means of a volume grating located thereon.
• a lighting device is described for example in DE 10 2009 028 984.4 or PCT / EP2010 / 058619.
• a substantially collimated light wave field is generated with a predeterminable polarization state.
• Such a lighting device can advantageously be made very flat.
• the illumination device is in this case designed and arranged such that the collimated light wave field propagates in the direction of the light modulator.
• the light modulator could be like that be configured to modulate the light of the light wave field in a transmissive or reflective manner.
• downstream of the light modulator in the direction of propagation of the light wave field is a component which realizes a field lens function, for example a Bragg grating.
• the illumination device is arranged between the light modulator and the diffraction device.
• This lighting device can be referred to in this case as a frontlight.
• the illumination device is arranged between the light modulator and the component which realizes the field lens function.
• the light modulator in this embodiment is designed as a reflective light modulator which can influence the phase of the light interacting with it.
• a ⁇ / 4 plate or a comparable optical component is arranged between the illumination device and the light modulator so that the polarization state of the light coupled out of the illumination device is rotated once during propagation in the direction of the light modulator by 45 degrees and after reflection at the light modulator and again Passage through the ⁇ / 4-plate or through the optical component by another 45 degrees is rotated.
• the light propagating in the direction of the illumination device is rotated by a total of 90 degrees relative to the light coupled out of the illumination device, so that the light reflected on the light modulator can pass through the illumination device-and in particular its volume grating-substantially undisturbed.
• the illumination device or the component that realizes the field lens function is followed by the first diffraction device, which realizes a diffraction of the light in a horizontal or vertical direction.
• the first diffraction device is followed by the second diffraction device, which realizes a diffraction of the light in a vertical or horizontal direction.
• a lighting device designed in the form of a backlight can also be used to provide the essentially collimated light wave field.
• the backlight in the propagation direction of the lightwave field then a transmissive working light modulator and the two diffraction devices are arranged downstream.
• a component implementing a field lens function could be arranged between the illumination device and the light modulator or between the light modulator and a diffraction device.
• a diffraction device can also be used in an auto-stereo display or in a conventional 2D display, in which the image content shown is only to be deflected or focused in the direction of the observer's eyes for safety reasons. The prerequisite for this is that this display has a coherent or partially coherent illumination.
• the elastic constants of the LC material also change, which has an influence on the orientation of the LC material under a given tension. This can be a Temperature change affect the phase modulation or the diffraction behavior of the diffraction device.
• Light modulator can be compensated. But preferred is a device that the occurrence of a
• Temperature gradient avoids by the diffraction device or the entire display are actively controlled temperature. In that regard, so could a temperature correction by a corresponding
• phase modulation in the diffraction device is based on a birefringent material
• the effective birefringence changes.
• an obliquely incident light beam would experience a different phase modulation than a vertically incident light beam.
• a change in the phase modulation by activation is only possible to a limited extent.
• the thickness of the LC layer would increase or decrease slightly from the center to at least the left and right margins, typically by 10 percent at 20 degrees oblique incidence of the light.
• the thickness of the LC layer would increase or decrease slightly from the center to at least the left and right margins, typically by 10 percent at 20 degrees oblique incidence of the light.
• the angle of incidence could also be compensated by the control voltage of the diffraction device.
• a light incidence may in principle come to a crosstalk of a light beam to a neighboring pixel of the diffraction device.
• Crosstalk can be reduced by reducing the layer thickness of the LC, for example by using materials with high birefringence.
• this can in principle be compensated by structured electrodes on both substrates and / or an offset arrangement of electrodes on both substrates of the diffraction device.
• a compensation of an oblique passage through the diffraction device due to the optionally provided component for the realization of the field lens function could be effected in that the thickness of the LC layer of the diffraction device is adjusted accordingly or that both substrates of the diffraction device have correspondingly offset arranged electrodes.
• the component which realizes the field lens, at each location of the component has a predetermined and therefore known angular deflection of the component passing through the light. In that regard, the angle of incidence for a predeterminable position on the diffraction device is known.
• the drive circuits can be accommodated on the substrate by means of TFT (Thin Film Transistor).
• TFT Thin Film Transistor
• circuits in CoG (Chip on Glass) technology can be applied to the substrate to drive the electrodes.
• the diffraction device is designed in such a way that the diffraction device can be used to set or write in a specifiable grid-shaped diffraction structure which extends only in one direction.
• the diffraction structure inscribed in the diffraction device is merely a linear lattice structure. This lattice structure may have binary or discrete or continuous profiles or partially mixed forms thereof.
• the diffraction device is designed in such a way that the diffraction structure which can be adjusted by means of the diffraction device can be changed in the periodicity.
• the diffraction device could have essentially linearly formed electrodes which are arranged essentially parallel to one another and which are arranged on a first substrate.
• the electrodes could thus be strip-shaped.
• the first or a substrate of the diffraction device could have a surface-shaped electrode which differs from those in the Essentially mutually parallel electrodes of the substrate is isolated insulating.
• the diffractive device could comprise a second substrate which is spaced from the first substrate.
• the second substrate could have a planar electrode and / or a plurality of substantially linearly formed and substantially mutually parallel electrodes.
• the second substrate has a plurality of substantially linearly formed electrodes arranged substantially parallel to one another, these electrodes could be arranged substantially opposite to the linearly formed electrodes of the first substrate or with a predeterminable lateral offset. The orientation of the electrodes of both substrates would be substantially parallel.
• the electrodes of the light modulation device with which, for example, a substantially sawtooth curve can be generated with a nearly vertical sloping edge, comparable to the representation from FIG. 3, in a preferred embodiment between two substrates at least one intermediate electrode layer is provided.
• the intermediate electrode layer has electrodes. Depending on the specific configuration of the intermediate electrode layer, electrodes could be arranged on at least one surface of the intermediate electrode layer. Particularly preferably, four intermediate electrode layers are provided between two substrates.
• the at least one intermediate electrode layer is preferably aligned parallel to a surface of a substrate. Both the electrodes provided on the substrates and the electrodes of the intermediate electrode layer can be electrically controlled individually in order to be able to realize a predetermined electrical potential curve as accurately as possible to a predetermined or desired ideal potential profile between the two substrates.
• the electrodes of the intermediate electrode layer are preferably substantially linear, substantially parallel to one another and aligned in a predeterminable direction.
• the electrodes of the interelectrode layer could have a grating period substantially corresponding to the grating period of the electrodes arranged on a substrate.
• the distance between a substrate and an adjacent intermediate electrode layer and / or between two adjacent intermediate electrode layers can be predetermined. This distance could correspond to a fraction of the distance between two adjacent electrodes or a fraction of the grating period of the electrodes of the substrate or the interelectrode layer.
• the width of the electrodes transverse to the longitudinal direction of the electrodes 1 micron, the distance between two adjacent electrodes 1 micron, the distance between the first substrate and the adjacent thereto intermediate electrode layer 0.5 microns, the distance between the intermediate electrode layer and the adjacent thereto intermediate electrode layer also be 0.5 microns.
• the distance between a substrate and an adjacent intermediate electrode layer or between two adjacent intermediate electrode layers is smaller than the distance between two adjacent electrodes, namely half of this value and could be even smaller.
• the electrodes of the first and / or second substrate and / or of an intermediate electrode layer which are formed linearly and arranged parallel to one another could be aligned in a predeterminable direction.
• the orientation of the linearly formed electrodes of the first substrate which are arranged parallel to one another and to the orientation of the electrodes of the second substrate which are formed in a linear manner and parallel to one another could have a predeterminable angle which lies in a range between 0 and 90 degrees.
• the angle has a value of substantially 0 degrees.
• this angle has a value of, for example, 10 degrees.
• the alignment of the linearly formed and mutually parallel electrodes of a substrate to the orientation of the linearly formed and mutually parallel electrodes of an intermediate electrode layer could have a predeterminable angle which lies in a range between 0 and 90 degrees, preferably 0 degrees. Further comments on this are given elsewhere.
• a plurality of electrodes of a substrate or an intermediate electrode layer are combined to form a segment.
• the electrodes combined to form a segment are actuated jointly in at least one operating state of the diffraction device.
• Such an activation could in particular comprise a substantially simultaneous shutdown or the transfer of the electrodes of a segment to a predeterminable electrical potential.
• a plurality of segments may be provided per substrate or intermediate electrode layer.
• Such an embodiment can be used in a particularly advantageous manner in a segmented illumination device (scanning backlight or scanning frontlight) in which individual segments (strip-shaped regions) are switched on or off or scanned in a time-sequential manner.
• the switching on and off of the segment-wise illumination device also a synchronized scanning off of the diffraction device or the light modulator 12.
• the electrodes 26 of the first substrate of the diffraction device are for example at an angle of 80 degrees to the strip-shaped Off-state electrodes 72 (which could be arranged on the second substrate) can be arranged and, for example, driven into 5 individual groups, as shown schematically in FIG. not shown in Figure 19) at an angle of 90 degrees to the off-state electrodes 72 of the second substrate (not shown in Figure 19) combined into segments 74.
• the electrodes 26 can each be charged with a different specifiable voltage
• Numbers 1 to 5 and U OFF in the lower part of FIG. 19 indicate that the electrodes 72 of a segment 74 can each be subjected to the same voltage. Since the scanning of the illumination device generally takes place synchronously in time for the writing of pixel contents into the light modulator, grouping of the off-state electrodes 72 into segments which are arranged or can be controlled in synchronism with the writing segments of the light modulator is advantageous. Accordingly, the resulting area of the off-state electrodes 72 of a segment could be shaped to be substantially overlapping the area of a segment of the illumination device.
• the off-state electrodes 72 could be formed into segments corresponding to the successively described and successively illuminated light modulator segments and / or grouped.
• the strip-shaped off-electrodes can also be designed parallel to the scanning direction of the illumination, which is the F-comb structure (ie the off-state electrodes 72 are substantially perpendicular to the electrodes 26 aligned) avoids the off-state electrode 72, which is shown in Fig. 19, for example.
• first substrate a flat ITO electrode
• an LC layer for example with a 3 ⁇ m thickness
• the electrodes of the first and / or second substrate and / or of an intermediate electrode layer formed in a linear manner and arranged parallel to one another could be aligned substantially parallel to one another.
• the electrodes arranged in the different layers or on the substrates are each aligned parallel to one another.
• the electrodes of the first and / or second substrate are transparent to the light used.
• the first and / or the second substrate is transparent to the light used.
• the refractive index of the electrodes substantially corresponds to the refractive index of the substrate.
• the electrode material and the substrate material are selected or designed such that they have substantially the same refractive index. This is especially intended for the light of the wavelengths used.
• a material is arranged according to a preferred embodiment, with which local changes in the refractive index for at least one polarization direction of the light by adjusting the Material influencing tax variable is achievable.
• the control variable influencing the material could be electrical voltages or electrical current, with the result that the individual elements of the material change accordingly in their orientation and / or in their optical property.
• the material could comprise liquid crystals or a polymer layer-in particular a polyimide layer-with liquid crystals or with elongated nano-particles.
• the nano-particles could have metallic carbon nanotubes (Carbo Nano Tubes) or nano-particles which have a permanent electrical dipole distribution. It could also be used nano-particles which have a belibige shape, which are designed to be birefringent for the light used and which can be aligned by, for example, an electric field in their spatial orientation.
• the material could be a relatively stable and suitably formed polymer layer with liquid crystals or with have elongated nano-particles in the interstices of the polymer layer, on which the electrodes of the intermediate electrode layer are applied directly during production.
• the polymer layer must be coated with a thin protective layer before the electrodes of the interelectrode layer can be applied to this protective layer to prevent the electroconductive material forming the electrodes of the interelectrode layer from entering the polymer layer.
• the material could comprise a flexible or viscous transparent layer having nano-particles mixed therein.
• the elongated nano-particles could, for example, be realized in the form of metallic ellipsoids which have a size which is smaller than ⁇ / 2n.
• ⁇ is the wavelength of the light used
• n is the refractive index of the medium or of the material in which the metallic ellipsoids are embedded.
• the metallic ellipsoids and the embedding medium would be the material mentioned above.
• the metallic ellipsoids have an electric dipole. Free electrons of the dipole can not vibrate in the electric field induced by the incident light in an occupation direction perpendicular to the major axis of the dipole.
• substantially parallel metallic ellipsoids represent anisotropy.
• birefringence can be realized by the metallic ellipsoids and their embedding medium, which depends on the orientation of the metallic ellipsoids.
• a comparable mode of action is present in metallic Carbo Nano Tubes whose geometry can be adjusted by process parameters during production.
• the length of the metallic Carbo Nano Tubes is also chosen smaller than ⁇ / 2n.
• metal molecules of the same order of magnitude could be used with two main axes which differ significantly in their length.
• liquid crystals could be arranged between the first and the second substrate and / or between a substrate and an intermediate electrode layer adjacent thereto and / or between two adjacent intermediate electrode layers, which crystals can be influenced in their orientation by applying a specifiable electrical voltage to the electrodes
• the electrodes of the first and / or the second substrate preferably each have insulating layers, so that the liquid crystals are not in electrical contact with the electrodes.
• the insulating layer is likewise to be selected such that the refractive index is largely matched to that of the electrodes and / or to the substrate and that the insulating layer is transparent to the light used. In this case, it would be possible to compensate for any height differences which may be caused by the application of the electrode material on the substantially planar substrate with the insulating layer.
• the insulating layer could also form a substantially planar surface to the layer of liquid crystals.
• a diffraction device based on liquid crystals may have a similar structure to an ECB-SLM (Electrically Controlled Birefringence).
• ECB-SLM Electrically Controlled Birefringence
• an orientation of the liquid crystals is largely parallel to Substrate by surface forces. In this plane parallel to the substrate, a direction is given during production (for example by mechanical rubbing).
• a layer could be provided with which the liquid crystals can be preoriented, for example by the mechanical introduction (eg by brushing) of corresponding recesses.
• the alignment of the LC molecules on the surface of a substrate preferably takes place parallel to the longitudinal direction of the electrodes, since sharper transitions in the LC orientation between adjacent electrodes when applying a voltage are then possible.
• the phase value that is realized at a specific position in the diffraction device can depend not only on the voltage at one electrode but also on the voltage at at least one neighboring electrode.
• phase SLM in which an activation for realizing a phase value for this pixel is generally independent for each pixel
• These voltage values may e.g. stored in stored form for the control ready.
• an arrangement of the electrodes on the opposite substrates can be helpful, as shown in FIG. 7.
• diffraction structures are generated with which local phase changes of the light interacting with the diffraction structures of the diffraction device can be realized (phase grating). It could be problematic to realize small periods of the diffraction structures, since possibly only a few electrodes are arranged in a small space, for example only 5, in order to set a predefinable phase adjustment of the diffraction device for a specific operating state.
• a preferred example of a diffraction structure or a predefinable phase adjustment is a sawtooth profile, which can be realized, for example, with the LC layer of the diffraction device. This is shown in FIG.
• the electrode arrangement of the electrodes shown in FIG. 8 is comparable to that according to FIG.
• ie at the top is a planar electrode 32 and opposite line-shaped electrodes 26 are arranged in a plane E 1 (the substrates are not shown in FIG. 8).
• ⁇ (x) an example of a set phase characteristic of the LC layer is shown, which results for the diffraction device traversing light when the electrodes 26 are subjected to a distribution of voltages to the potential U c of the electrode 32.
• the electrodes are designed to be very wide, ie, for example, the duty cycle is increased from 0.5 to 0.8, so that the electrodes occupy 80% of the period, then one less would Stepped phase ramp can be realized, but the range of the 2 ⁇ (phase) jump or 2 ⁇ -stage, which is indicated by the reference symbol PS in Fig. 8, would be much less steep than is the case in Fig. 8 ,
• This form of general, locally undifferentiated and non-variably selectable smoothing represents a low-pass filter, ie reduces the highest spatial frequency still to be represented of the synthetic, variable phase grating.
• a buried second layer of transparent electrodes 54 arranged in the plane E 2 which for example has the same spacing of the first electrode layer and the same or a different duty cycle, can be used to achieve in a targeted manner a smoothing of the step profile at the locations where a phase ramp is to be realized while allowing a sharp edge of the 2 ⁇ stage. In Fig. 9 this is shown.
• the electrodes 54 of the plane E 2 are set, for example, to the mean value of the voltage of their two adjacent electrodes of the plane E 1 . From this rule, however, the electrodes 54 are excluded from the plane E 2 , which lie directly below the 2 ⁇ jump to be realized. They carry a voltage U 2 ⁇ , which realizes the sharpest possible edge.
• the advantage of a second electrode comb structure buried is that at the boundary of the resolution of, for example, used contact copy lithography, line widths can be used that are, for example, twice as wide as the line widths that would have to be used if both electrode comb structures in FIG a common level.
• the plane at the upper substrate (not shown in FIG. 10) is also designed in an advantageous embodiment in the form of two superimposed electrode comb structures in two different planes E 3 and E 4 . This is shown in FIG. In comparison to the embodiment of FIG. 9, this results in a steeper course of the edges of the phase stages.
• the electrodes 26, 54 are for example made of ITO (indium tin oxide) and embedded in high refractive glass, such as SF66, so as not to be optically effective as a phase grating.
• electrodes are arranged in at least two different planes parallel to a surface of the substrate on at least one substrate of the diffraction device.
• the arranged in the different planes electrodes may be laterally offset from each other.
• the dimensions of the electrodes and / or their distances between them may differ or be substantially the same.
• the electrodes of the diffraction device are connected in such a way that an electric field distribution is established in the diffraction device, with which a sawtooth-shaped refractive index distribution with a predeterminable periodicity results, at least in regions.
• an electric field distribution is established in the diffraction device, with which a sawtooth-shaped refractive index distribution with a predeterminable periodicity results, at least in regions.
• This can be achieved, for example, in that, with respect to one direction, the adjacent electrodes are each subjected to different electrical voltages.
• an electrical field results between the two substrates of the diffraction device with which the material arranged between the two substrates can be influenced such that a sawtooth-shaped refractive index profile is established. This is an active state in which two- and / or three-dimensional image contents are generated.
• the electrodes of the diffraction device are connected in such a way that an electric field distribution is established in the diffraction device with which a substantially homogeneous refractive index distribution results.
• adjacent electrodes of a substrate could each be subjected to electrical voltages of different signs, so that the electric field lines extend from an example positively charged electrode to the two adjacent negatively charged electrodes - and not to the oppositely disposed electrode of the other substrate.
• an electric field distribution results, the electric field lines of which have a relatively small angle relative to the surface of the substrate, so that in a middle region between the two substrates, resulting electric field lines result, which are aligned substantially parallel to the surfaces of the two substrates.
• This is an inactive state in which no two- and / or three-dimensional image content is displayed.
• the material arranged between the two substrates can very quickly be converted into a defined neutral state, from which the material can be returned to an active state, in which another diffraction structure is realized.
• the electrodes of the diffraction device are already wired in the setting of a substantially homogeneous refractive index distribution such that an electric field distribution results which prepares the refractive index distribution to be generated next.
• the electrodes of the diffraction device are each subjected to an initially increased electrical voltage over time, as is necessary for setting the refractive index distribution to be generated.
• the electrical voltage is then adjusted to values which are required for setting the refractive index distribution to be generated.
• a light modulation device for displaying two or three-dimensional image contents may require fast reaction times of the diffraction device and of the light modulator.
• possibilities are shown with which the reaction times of the diffraction device or of the light modulator can be reduced, so that a light modulator can be used which does not have a frame rate in the order of 150 Hz and higher.
• the light modulator and the diffraction device could be temporally sequentially exposed to light of different wavelengths, for example light of the primary colors red, green, blue.
• the diffraction device is adjustable synchronously with the respective lighting situation.
• the light modulator could be controllable with the control device in such a way that information for a left or right eye is written into the entire light modulator.
• the light wave field changed by the light modulator for the left or right eye can be deflected in each case into the left or right eye of at least one observer.
• the information for the left or the right eye is sequentially written in the light modulator.
• the light modulator could include first and second regions, e.g. Columns, which are each describable with information for a left and a right eye.
• the first and second regions of the light modulator are each associated with first and second regions of the diffraction device.
• the light modulator and the diffraction device can be controlled in such a way that the light wave field changed by the first regions of the light modulator - which has been substantially changed by the information inscribed in the first regions of the light modulator - is directed from the first regions of the diffraction device to a left eye of at least one observer becomes.
• the light wave field changed by the second regions of the light modulator - which has been changed substantially by the information inscribed in the second regions of the light modulator - is directed by the second regions of the diffraction device to a right eye of the at least one observer.
• the first and second regions of the light modulator are alternating with each other and arranged repeatedly. Alternatively or additionally, the first and second regions of the light modulator are aligned vertically, in particular are columns of the light modulator.
• the individual pixels of the light modulator color filters could be assigned and / or the individual areas of the diffraction could be assigned color filter.
• the light modulator could be followed by a diffraction device for a beam deflection acting essentially in the horizontal direction.
• a means is provided, for example a suitable scattering foil with which a widening of an illumination area - a so-called sweet spot - takes place in the vertical direction.
• a time-sequential illumination of the light modulator and the diffraction device with light of different wavelengths with a synchronous writing of a tuned to the light of the respective wavelength diffraction structure may be provided in the diffraction device to each of these wavelengths to achieve the same or a predetermined deflection angle.
• the synchronous writing of image contents adapted to the light of the respective wavelengths into the light modulator can likewise be effected in a time-sequential manner for these wavelengths.
• a light modulator with spatial color multiplexing, so with color filters can be used.
• the image content to be displayed for light of several wavelengths can then be written into the light modulator synchronously or as a function of the lighting situation or in a single encoding process.
• This allows the combination of a light modulator with a longer reaction time with a diffraction device with a shorter reaction time.
• the light modulator can have an image refresh rate of 120 Hz and the diffraction device a refresh rate of 360 Hz.
• the individual pixels of the light modulator color filters can be assigned, the respective color filter of the pixels suitably correspond to the commonly used three primary colors, eg red, green , Blue.
• the pixels of the light modulator are described with information in the general case regardless of their respective color assignment.
• the light modulator when the writing process is completed for all the pixels of the light modulator, the light modulator is subjected to time sequential light of different wavelengths - corresponding to the primary colors used color filter.
• the modulation of the illumination is possible in the kHz range and not the time-limiting factor.
• the individual pixels of the light modulator act according to the color filters assigned to them.
• the diffraction device is driven synchronously to the respective lighting situation.
• the writing process is dependent on the color assignment. All the pixels of a base color are first written in time sequential order, those of other primary colors in the same order as the subsequent application of light of the primary colors. For example, all red pixels are written first, then all greens and then all the blue ones. Then all the red pixels are lit, then all green and then all blue.
• the drive matrix of the three primary colors of the RGB light modulator can be understood as an interleaving of three monochrome light modulators, which have a phase shift of 2 ⁇ / 3 in the temporal drive, i. each offset by one third of the refresh rate to each other.
• the available reaction time in which the pixels can set their modulation state after writing to light exposure of the respective primary color, for all primary colors a minimum value corresponding to the writing and Beauftschungszeit the other colors.
• Electrode structure has only substantially linearly formed electrodes arranged substantially parallel to one another
• spatial multiplexing is also possible, for example, from
• Light modulator is deflected at a certain angle.
• Light adjacent red, green or blue pixels can be deflected at the same angle, for example, by means of adapted diffraction structures in the individual spatial regions of the diffraction device.
• image content for the left or the right eye of a viewer are intended to be deflected at different angles.
• the information for the left and the right eye of a viewer in the form of a spatial multiplexing can be written simultaneously in the light modulator.
• both the light modulator and the diffraction device have color filters.
• Multiplexing can also be performed by assigning different sections of the diffraction device to parts of a pixel column of the light modulator. For example, light from a left half of a pixel column with its associated spatial portion of the diffractive device may be deflected in a particular direction and light from a right half of a pixel column may be deflected in a different direction with another portion of the diffraction device associated therewith. This can be used to display the same image content for the same eye of multiple viewers.
• a superposition of a plurality of deflection functions can also be written into the diffraction device.
• a superposition leads to a complex-valued deflection function.
• this could be approximated by a phase function for writing in a phase-modulating diffraction device.
• known methods such as iterative Fourier transformation (IFTA) may be used.
• IFTA iterative Fourier transformation
• a diffraction device which diffracts the light by modulating both its amplitude and its phase.
• Diffraction by modulation of amplitude and phase can also be effected by successively arranging two diffraction devices in which the electrode structure has substantially linearly formed electrodes arranged substantially parallel to one another and of which one diffraction device modulates the amplitude of the light and the second diffraction device Diffraction device modulates the phase of the light.
• the diffractive devices are based on the use of liquid crystals, then modulation of either amplitude or phase can be adjusted by a suitable choice of the polarization of the light, such as by using polarizers and / or retardation plates.
• Another possibility for displaying the same image content with the light modulator for the same eye of several observers - ie for several left eyes or for several right eyes - is to combine again a light modulator with a lower frame rate and a diffuser with a higher frame rate , While essentially constant information - for example a hologram or a stereo image for the left eye - remains inscribed on the light modulator, the diffraction device successively deflects light to the position of the same eyes of the individual observer.
• the information for the left eye would be written in and with the diffraction device in turn for 3 different colors of light directed to the left eyes of 2 observers.
• the information for the right eye would be written into the light modulator, sequentially illuminated with light of the respective color, and redirected to the right eye of two or more viewers with the diffraction device synchronously with the lighting situation one after the other for the respective colors.
• the writing of the right-eye information and the blue color into the light modulator can already be performed while still guiding the red or green color light to the left eyes with the diffraction device.
• the diffraction device is followed by a further diffraction device.
• the further diffraction device is a diffraction structure of a
• Adjustable periodicity which has a predeterminable direction or structure, which differs from the predeterminable direction or structure of the periodicity of a set diffraction structure of the
• Light modulator downstream (first) diffraction device distinguishes. This can be a
• the two diffraction devices could be arranged relative to each other such that the predeterminable direction or the structure of the periodicity of the diffraction structure of the (first) diffraction device is substantially perpendicular to the predeterminable direction or structure of the periodicity of the diffraction structure of the further diffraction device.
• the first and the second diffraction device could each have a substrate with substantially linearly configured electrodes arranged substantially parallel to one another and aligned in a predeterminable direction.
• the two diffraction devices are arranged relative to one another such that the linearly formed electrodes of the first diffraction device are aligned substantially perpendicular to the linearly formed electrodes of the second diffraction device.
• the electrodes of the two diffraction devices can lie in planes which are arranged essentially parallel to one another.
• the electrodes of the diffraction device which are substantially linear and arranged substantially parallel to one another, are oriented at an angle relative to the horizontal in such a way that a light distribution of the light diffracted at the diffraction device results in a viewer plane, which results in the occurrence of light intensities in observer eyes which are adjacent to observer eyes with a visibility area are largely suppressed.
• This is particularly important when the light mutation device according to the invention is used for a display for displaying holographic three-dimensional image contents, which operates according to the principles described in WO 2006/0669191 A1.
• a 3D scene coded into the light mutation device can be holographically reconstructed with at least partially coherent light for at least one observer.
• the observer sees the reconstruction or the three-dimensional scene when his eyes coincide with the visibility region in the observer plane generated for his position. If the observer changes his distance from the display or moves laterally in front of the display, he is tracked to the visibility area.
• a position detection system determines the position of the Viewer eyes, and thus the deflection angle of the light beam from the optical axis of the display to the viewer eye, and updates the position data.
• the position detection system is connected to the light modulator via control means.
• the visibility range of a detected observer eye is specified for a region between two adjacent diffraction orders and thus two adjacent light source images. This prevents that an intensity maximum lies in this eye and disturbs the viewing of the reconstruction.
• the shape of the aperture of the modulator cell determines the distribution of the total intensity of a light source to its generated individual light source images.
• crosstalk of the intensities or perception of diffraction orders may occur in an eye adjacent to the currently generated visibility region. This can be reduced or completely suppressed with different approaches.
• a similar effect could be caused by the at least one diffraction device arranged downstream of the light modulator, which diffraction device is likewise to be reduced or suppressed. This can be achieved by the corresponding orientation of the electrodes at a predeterminable angle relative to the horizontal.
• the light modulator and / or the diffraction device has along at least one direction a periodic structure with a predeterminable periodicity.
• the light modulator typically has a matrix-like structure, i. a lattice structure in two different directions.
• the diffraction device preferably has a periodic structure in only one direction. Specifically, it is provided that the light modulator and the diffraction device have a periodic structure with a predeterminable periodicity.
• the periodicity of the diffraction device is smaller than the periodicity of the light modulator or the periodicity of the diffraction device is equal to the periodicity of the light modulator.
• the periodicity of the diffraction device could, for example, be smaller by a factor than the periodicity of the light modulator, which has a value which lies in a range between 2 and 150.
• the diffraction device has individual diffraction elements into which binary, discrete or continuous values can be set. These values could correspond in particular to adjusted orientations of the liquid crystals which cause corresponding phase changes of the light passing through the respective diffraction element of the diffraction device.
• the set values of the diffraction elements of the diffraction device form the diffraction structure.
• a diffraction element could be an electrode and the LC material arranged at this electrode.
• a field lens function for the display could be achievable in that predefinable phase terms are written into the diffraction device.
• a focusing optical component could be provided with which a field lens function for the display can be realized.
• the focusing optical component could be designed in the form of a Bragg grating predeterminable property.
• a temperature compensation could be provided, which has an active temperature control with at least one temperature sensor and at least one thermodynamic element - for example a Peltier element.
• a Peltier element can are used locally for cooling, for heating and / or for temperature measurement (U (T)).
• a temperature compensation could be realized by writing a predefinable phase curve in the light modulator.
• a predefinable deflection angle for light of different wavelengths would also be adjustable if the light modulator and the diffraction device are time-sequentially illuminated with light of different wavelengths.
• a diffraction structure tuned to the currently used wavelength of the light is written into the diffraction device. This can be done for the three primary colors red, green and blue, so that a color representation of the image content with the display is possible.
• the diffraction device is arranged adjacent to the light modulator.
• An optionally provided further diffraction device is arranged adjacent to the first diffraction device.
• Adjacent in this context is to be understood in particular as meaning that no further optical component is arranged between the light modulator and the diffraction device or between the two diffraction devices or that the respective components are arranged in spatial proximity to each other. With spatial proximity, a distance range of 0 to 10 mm could be designated. It is also conceivable that at least two of the following components are designed as a sandwich: the light modulator, the diffraction device and the further diffraction device. In this case, during the manufacturing process, one component has been directly attached to the other component. Individual components of the sandwich could have a common component, in particular a substrate. The component realizing the field lens function could also be integrated into the sandwich.
• a display according to the invention is characterized by a light modulation device according to one of claims 1 to 36.
• the display is designed such that stereoscopic image contents and / or stereoscopic multi-view image contents and / or holographic image contents can be displayed.
• Such a display (3D display) is thus able to display three-dimensional image content in three dimensions for human perception.
• the possible embodiments of the light modulation device reference is made to the preceding part of the description to avoid repetition.
• the 3D display according to the invention it is conceivable for the 3D display according to the invention to maintain the observer tracking, and to replace the information for the 3D scene with a 2D image content with respect to the displayed content.
• An additional optical device which comprises in the structure and in the form of a switchable scattering medium. When inactive or switched off, the medium is transparent. When switched on, the medium has a scattering effect. Suitable switchable scattering medium are, for example, polymer-dispersed liquid crystals (PDLC).
• PDLC polymer-dispersed liquid crystals
• the additional optical device could be arranged on the side of the display facing the observer, so to speak as the last optical component of the display. In the active state of the optical device, the diffraction device would be deactivated. This would realize the 2D mode of the 3D display. If the optical device is deactivated and the diffraction device is activated, the 3D display is in 3D mode. With this option, therefore, an additional component in the structure is required.
• the second preferred option is:
• the diffraction device itself is switched between two modes of operation.
• the diffraction device In the one operating mode (3D mode), the diffraction device is driven in such a way that it deflects light to a specific position.
• the diffraction device In the other operating mode (2D mode), the diffraction device is driven in such a way that it has a scattering function.
• a coded diffuser function is used. This can be realized for example by a random phase distribution or by a specifically optimized phase distribution, which is adjusted instead of a regular grid by appropriate control in the diffraction device. If two crossed diffraction devices are used, the first is used for horizontal and the second for vertical dispersion.
• Holographic displays use full-parallax holograms or single-parallax holograms.
• Single-parallax holograms represent a simplification with regard to the computation or coding effort.
• Single-parallax holograms permit, inter alia, the use of a lighting device which is coherent only in the coding direction or in the parallax direction. In one direction (the coding direction), one observer window can be generated, in another direction (perpendicular thereto) a sweet spot, cf., for example, WO 2006/027228 A1.
• a diffraction device for observer tracking usually requires coherent light. However, it is not necessary for there to be coherence over the entire surface of the diffraction device. Rather, it is sufficient for the function of the diffraction device if the coherence is present over a few periods of the grating.
• a pixel pitch of the SLM of, for example, 50 ⁇ m and a pitch of the diffraction device of 2 ⁇ m, it would be possible, for example, to coherently illuminate about 25 grating periods of the diffraction device, but to illuminate adjacent pixels of the SLM largely incoherently.
• the object mentioned above is achieved by the teaching of claim 40. Accordingly, the inventive method for producing a light modulation device according to one of claims 1 to 36 is used.
• the manufacturing method comprises the following method steps:
• step b for example, a thin polymer film containing liquid crystals or carbon nanotubes or metallic elliptical nanoparticles could be laminated on.
• a further material layer for example a further polymer film, could now be laminated on.
• step b) is an electrode having intermediate electrode layer on the
• Steps d) and e) can be performed at least once more.
• the first substrate and the at least one intermediate electrode layer could be aligned with one another in such a way that the electrodes of the first substrate formed in a linear manner and arranged parallel to one another are aligned substantially parallel to the electrodes of the intermediate electrode layer formed in a linear manner and arranged parallel to one another.
• Electrodes could be deposited by depositing an electrically conductive film of liquid or gas phase onto the substrate or onto the material layer.
• a photoresist is laminated, spin-coated or even sprayed on.
• the photoresist is exposed with a striped pattern. The exposure can be done eg in contact copy.
• the strips can also be produced in the form of a two-beam interference pattern.
• the exposed photoresist is eg with KOH developed (AZ Hoechst).
• the exposed lines of the conductive layer are etched away with a solution. The remainder, ie remaining photoresist is removed with Remover.
• the gaps between the electrodes could be filled by, for example, depositing a nonconductive, sufficiently transparent material from the liquid or gas phase.
• a polarizer which runs as a wire grid polarizer substantially parallel to the electrodes, several lines or electrically conductive structures of the wire grid polarizer can be contacted together, with. three or four lines together then can form an electrode of the diffraction device. The resulting electrodes can be contacted for electrical actuation from one side or from two opposite sides.
• ITO electrode lines can be applied parallel to the wire grid polarizer lines over these wire grid polarizer lines and in electrical contact with these wire grid polarizer lines. This could be done, for example, with the aid of areawise exposure processes (stitching), for which purpose the overlay error of 15 nm to be observed in semiconductor production need not be complied with. For the production of the ITO electrode lines provided here, an overlay error of 150 nm to 250 nm is sufficient. This has the advantage that the conductivity of the ITO electrode lines and the hereby electrically contacted wire grid polarizer lines is significantly increased compared to ITO structures alone and high switching frequencies can be achieved, for example> 1 kHz.
• wire grid polarizer as electrodes of a diffraction device is that the electrical conductivity is above the electrical conductivity of the ITO and in the far field of a holographic display no amplitude or phase modulation in the form of light, which is present in the individual diffraction orders, noticeable power. Together with ITO, this results in an even higher electrical conductivity, or the option to also use broken lines of the Wire Grid Polarizer.
• a substrate of the diffraction device comprises a planar electrode, which is isolated from the electrodes arranged substantially parallel to each other and / or the measure that the orientation of the linearly formed and parallel to each other electrodes of the first substrate to the orientation of the linearly formed and arranged parallel to each other electrodes of the second substrate or an intermediate electrode layer have a predetermined angle, which is in a range between 0 and 90 degrees, preferably 0 degrees.
• a predetermined angle which is in a range between 0 and 90 degrees, preferably 0 degrees.
• the switching time ie the time until a desired orientation of the LC is reached in a pixel of the display, an essential parameter that determines which frame rates the display can be operated. Often, not only a fast turn-on time, but also a fast turn-off time is required.
• the LC has a given surface orientation through an alignment layer.
• a reorientation of the LC takes place through an interaction of the dielectric anisotropy of the LC material with an applied electric field.
• the speed of this process can be influenced by the value of the field strength.
• a relaxation takes place back into the state determined by the surface orientation of the alignment layer.
• the speed of this relaxation is usually influenced only by material properties of the LC, such as its viscosity and is usually slower than the switch-on.
• a suitable electrode arrangement is to be specified which allows to apply electric fields which, on the one hand - move the LC orientation away from the surface orientation when switched on - and on the other hand - when switched off - also move back towards the surface orientation.
• the light modulation device for example, a sawtooth-shaped.
• a sawtooth-shaped By the grid of line-shaped electrodes in the diffraction device
• the sawtooth profile may have a variable out-of-plane orientation of the LC due to a corresponding out-of-plane field between the first and second
• Substrate can be adjusted.
• the line-shaped electrode arrangement also allows the application of a
• In-plane field With this, the turn-off can be accelerated by the LC molecules are moved back into their predetermined by the surface orientation in-plane orientation.
• other types of diffractive devices or light modulators based for example on IPS (in-plane switching) or FFS LM mode (fringe field switching), use an in-plane rotation of LC molecules in the field in combination with a surface orientation which also Plane is. Then, the above-described scheme with in-plane field for fast turn-off is not immediately applicable.
• the problems mentioned here can be solved with a light modulator or a diffraction device which has an LC layer between two substrates.
• the light modulator or the diffraction device is preferably used for phase modulation of circularly polarized light by substantially in-plane rotation or orientation of the LC molecules.
• the light modulator or the diffraction device comprises substantially linearly formed and substantially mutually parallel electrodes on the first and on the second substrate.
• the orientation of the linearly formed and mutually parallel electrodes of the first substrate has a predetermined angle to the alignment of the linearly formed and mutually parallel electrodes of the second substrate, which lies in a range between 0 and 90 degrees.
• the fine adjustment of the angle of the in-plane LC orientation can be adjusted by an electric field.
• the angular range of the LC orientations can be increased by an electric field and / or the resetting or switching-off process be accelerated by rapid reorientation of LC molecules.
• a substrate of the diffraction device or of the light modulator could have a planar electrode which is isolated from the electrodes arranged substantially parallel to one another.
• FIG. 17 (a) shows a plan view of the strip-shaped electrode arrangement, namely the electrodes 26, on the first substrate 28 and the rubbing direction R of the surface alignment layer and thus the orientation of the LC molecules 70 when no electric field is applied. This is inclined by a small angle ⁇ - in this example 10 degrees - against the perpendicular to the longitudinal direction of the electrodes 26. As a result, a direction of rotation of the LC molecules 70 is predetermined counterclockwise when a field is applied.
• the rotation takes place about the largest possible angle, so that the LC molecules 70 in the strong field can also be parallel to those on the first or lower substrate 28.
• This operating state is shown in Fig. 17 (b).
• the electrodes 72 on the second (e.g., upper) substrate 30 are arranged such that for this maximum angle of LC orientation they are inclined by a small angle - e.g. B. ⁇ - are inclined against the longitudinal axis of the LC.
• a field is applied to the electrodes 72 on the upper substrate 30
• fast reverse rotation of the LC molecules 70 occurs in the state shown in Fig. 17 (a).
• the accelerated switching off can take place globally or, for example, also line by line in a light modulator or in a diffraction device.
• the electrodes 26 on the first substrate 28 must be individually controllable in a diffraction device or pixelated in a light modulator in order to set a desired phase profile or pixelated phase values.
• the electrodes 72 on the second substrate 30 may, for example, use a common control signal which globally switches a whole line of a light modulator or the diffraction device back to the same surface orientation of the LC molecules.
• a diffraction device generally uses very finely structured electrodes 26 on the first substrate 28, since larger diffraction angles can be achieved with a small electrode pitch.
• the electrodes 72 on the second substrate 30 can advantageously be coarser in structure since they have no direct relation to the diffraction angle.
• the orientation of the linearly formed and mutually parallel electrodes 26 of the first substrate 28 has a predetermined (small) angle ⁇ to the preferred direction R of the surface alignment layer.
• the orientation of the substantially linearly formed and mutually parallel electrodes 72 of the second substrate 30 has an angle ⁇ to the orientation of the electrodes 26 of the first substrate 28, which may be, for example, 90 degrees.
• Another option that supports fast reverse rotation of the LC molecules 70 would be to momentarily apply an out-of-plane field between the electrodes 26, 72 of the two substrates 28, 30, with which the LC molecules 70 are rotated out of plane but then move back to the position of surface orientation faster than with a pure in-plane reverse rotation.
• These arrangements can also be combined with a switchable surface orientation, as described in DE 10 2009 059 095.1, which is used to achieve a larger rotation angle range of the LC molecules.
• 18 shows a plan view of an embodiment in which an enlargement of the rotational angle of the alignment of the LC molecules 70 is made possible by the electrodes 26, 72 in conjunction with a static surface alignment layer.
• FIG. 18 (a) shows a plan view of the electrodes 26 on the first substrate 28 and the surface orientation R of the static surface Alignment layer, in this case as in Fig. 17 (a).
• FIG. 18 (b) shows a plan view of the electrodes 72 on the second (upper) substrate 30.
• Switching is thus effected by selectively applying a voltage to the second substrate 30 (as indicated by the lower LC 70 in Fig. 18 (b)) or not (as indicated by the upper LC 70 in Fig. 18 (b)). and to select a direction of rotation through another pre-alignment of the LC molecules 70. Subsequently, the fine adjustment of the total rotation angle of the LC molecules 70 is effected by the electrodes 26 on the first substrate 28.
• the switching off or the resetting of the LC molecules 70 can additionally, as shown in FIG. 17, by applying an electric field to the second substrate 30 be accelerated. In this way, an increase of the adjustable angle range of the LC orientation without active / variable surface alignment layer can be achieved.
• FIG. 1 is a plan view of a first embodiment of the present invention
• FIG. 2 is a plan view of a second embodiment of the present invention
• FIG. 3 shows a schematic diagram representation of an example of a diffraction structure inscribed in the diffraction device
• FIG. 4 is a partial exploded view of a first embodiment of a structure of a diffraction device
• FIG. 5 is a sectional view of a part of the diffraction device of Fig. 4,
• 6 is a sectional view of a part of another embodiment of a diffraction device
• 7 is a sectional view of a part of another embodiment of a diffraction device
• FIG. 12 is a schematic representation of the orientation of the electrodes of a first and a second diffraction device
• 16 is a schematic diagram of a voltage curve as a function of the time with which an electrode of the diffraction device can be acted upon
• the light modulation device 10 has a
• Light modulator (12, SLM) and a control device 14 on.
• the light modulator 12 is illuminated with a collimated light wave field 16, which is indicated by the arrows shown in Fig. 1.
• the light modulator 12 is illuminated with a collimated light wave field 16, which is indicated by the arrows shown in Fig. 1.
• Phase and / or the amplitude of the collimated lightwave field 16 can with the light modulator 12 in
• Dependence of the location of the light modulator 12 are changed.
• the light modulator 12 on individual (enlarged) pixels 18, which are arranged in a matrix.
• Light wave field 16 the light modulator 12 at least one controllable diffraction device 20 downstream.
• the diffraction device 20 is also controlled by the control device 14, but could be controlled by a separate control unit.
• the diffraction device 20 has a variable diffraction structure. With the diffraction structure, the light wave field 16 changed by the light modulator 12 becomes definable
• FIG. 3 shows a schematic diagram of an example of a diffraction structure 22 inscribed in the diffraction device 20.
• the phase delay that can be impressed on the light wave field 16 by the diffraction device 20 is shown as a function of the pixels or of the location in the horizontal direction / X direction of the light modulator 12.
• the diffraction device 20 is designed in such a way that the diffraction structure 22 which can be adjusted by means of the diffraction device 20 can be changed in the periodicity. Concretely, the periodicity 24 of the diffraction structure 22 can be increased or decreased.
• the shape of the diffraction structure 22 is variable.
• a rectangular function, a sawtooth function, a sine function or another predefinable function can be used be recorded by discrete steps or continuously (depending on the specific structural design of the diffraction device 20) approximately or exactly in the diffraction device 20.
• FIG. 4 shows, in a partially exploded view, an embodiment of a diffraction device 20 with electrodes 26 formed substantially linearly and arranged substantially parallel to each other.
• the electrodes 26 are arranged on a first substrate 28 and extend in FIG. 4
• Electrodes 26 can be contacted electrically and of a not shown in Fig. 4
• Control device can be acted upon by electrical voltage.
• the diffraction device 20 has a second substrate 30, which is arranged at a distance from the first substrate 28.
• the second substrate 30 has a planar electrode 32.
• FIG. 5 shows the diffraction device 20 in a sectional view, wherein the diffraction device 20 is to be continued to the left and to the right or both sides in such a way that the diffraction device 20 extends over the entire width of the light modulator 12 shown in FIG extends.
• the width B of the strip-shaped and provided on the first substrate 28 electrodes 26 is in this embodiment, 1, 5 microns.
• the width of the gap G between two adjacent electrodes 26 is 0.5 ⁇ m.
• Other values for the stripe width of the electrodes 26 and the spaces between adjacent electrodes 26 are possible and depend in particular on the application of the display and the specific embodiment of the light modulator 12.
• 6 shows a sectional view of a further exemplary embodiment of a diffraction device 20, in which case strip-shaped electrodes 26 are provided both on the first substrate 28 and on the second substrate 30.
• FIG. 7 shows in a sectional view a further exemplary embodiment of a diffraction device 20, which is of construction substantially similar to the diffraction device 20 shown in FIG.
• the electrodes 26 arranged on the upper substrate 28 are laterally offset relative to one another with respect to the electrodes 26 arranged on the lower substrate 28.
• a liquid crystal (LC) layer 34 Between the first substrate 28 and the second substrate 30 of the diffraction device 20 shown in FIGS. 5 and 6, there is provided a liquid crystal (LC) layer 34.
• the liquid crystals can be influenced in their orientation by applying a specifiable electrical voltage to the electrodes 26.
• Reference numeral 36 denotes an insulating layer which prevents the liquid crystals from being in electrical contact with the electrodes 26 and 32, respectively.
• FIG. 2 shows a further exemplary embodiment of a light modulation device 10 according to the invention, in which a further diffraction device 38 is arranged downstream of the first diffraction device 20 in the propagation direction of the light wave field 16.
• a diffraction structure of a periodicity is adjustable, which has a direction Y or structure which differs from the direction X or structure of the periodicity 24 of a set diffraction structure 22 of the (first) diffraction device 20 downstream of the light modulator 12.
• the two diffraction devices 20, 38 are arranged relative to one another such that the direction X or the structure of the periodicity 24 of the diffraction structure 22 of the first diffraction device 20 is substantially perpendicular to the direction Y or structure of the periodicity of the diffraction structure of the further diffraction device 38.
• a tracking of the viewer's eyes of a viewer in the horizontal direction X can take place.
• a tracking of the viewer's eyes of a viewer in the vertical direction Y can be done.
• the first and second diffraction devices 20, 38 each have a substrate with electrodes 26 that are substantially linear and are arranged substantially parallel to one another.
• the two diffraction devices 20, 38 are arranged relative to one another such that the linearly formed electrodes 26 of the first diffraction device 20 are aligned substantially perpendicular to the linearly formed electrodes 26 of the second diffraction device 38.
• the light modulator 12 and the first and the second diffraction means 20, 38 are driven by the control device 14.
• the light modulator 12 and the diffraction device 20 have a periodic structure with a predeterminable periodicity, wherein the periodicity of the diffraction device 20 is smaller than the periodicity of the light modulator 12.
• the periodicity of the diffraction device 20 in dependence on the control and the specific embodiment is 2 microns.
• the periodicity of the light modulator is 50 ⁇ m in the horizontal and in the vertical direction. To avoid moiré effects, a non-periodic period can also be used.
• the electrodes 26 of the diffraction device 38 can be regarded as individual diffraction elements into which - in cooperation with a part of the liquid crystal layer 34 - discrete or continuous values can be set by applying presettable electrical voltages.
• a field lens function of the display can be achieved by providing a focusing optical component 40 in the form of a Bragg grating. With the component, the light beams of the light wave field 16, which pass through the light modulator 12, are focused or deflected in the direction of the central observer positions 42.
• the central viewer positions 42 are arranged symmetrically to the central axis 44 of the light modulation device 10 and at a distance D from the light modulator 12.
• the central viewer positions 42 consist of two observer windows 46, 48.
• the diffraction device 20 makes it possible to ensure a lateral tracking of the observer windows 46, 48 to the current position of the viewer eyes 50, 52 by inscribing corresponding diffraction structures 22 in the diffraction device 20 become.
• the tracked observer windows are identified by reference numerals 46 'and 48'.
• the display which has a light modulation device 10 shown in FIGS. 1 or 2 and / or which is designed according to one of claims 1 to 20, may in concrete be configured such that stereoscopic and / or stereoscopic multi-view image contents and / or or holographic image content can be displayed.
• FIG. 11 shows, in a schematic side view, a further exemplary embodiment of a diffraction device 20, which is formed by the structure substantially comparable to the diffraction device 20 shown in FIG.
• a diffraction device 20 shown in Fig. 11 three intermediate electrode layers 56 are provided.
• Each intermediate electrode layer 56 has a plurality of electrodes 58 whose width, spacing and arrangement substantially correspond to the width, spacing and arrangement of the electrodes 26 which are arranged on the first substrate 28 and on the second substrate 30, respectively.
• a material 62 is arranged which has a polyimide layer.
• the polyimide layer is such that, on the one hand, it has an essentially form-invariant structure and, on the other hand, has spaces (not shown) in which liquid crystals are arranged.
• the liquid crystals freely movable in the polyimide layer can be aligned in accordance with the field distribution of the resulting electric field and accordingly influence the light passing through the diffraction device 20.
• the material 62 is likewise arranged in each case. With solid lines in each case, insulating layers 64 are indicated, which prevent in the manufacturing process of the diffraction device 20 according to the invention that the electrode material of the electrodes 58 applied in a coating process diffuses into the material layer 62.
• the electrodes 58 of the intermediate electrode layers 56 could be arranged in the respective intermediate electrode layer 56 laterally offset from the electrodes 26 of the first and second substrates 28, 30, respectively. It is also conceivable to choose the width and the respective spacing of the electrodes 58 of at least one intermediate electrode layer 56 differently from the width or the spacing of the electrodes 26.
• FIG. 12 shows a schematic representation of an embodiment of an alignment of the electrodes 26 of a first diffraction device 20 with respect to the electrodes 26 of a second one
• the electrodes 26 of the first diffraction device 20 are under a
• Diffraction devices 20 'are at an angle ⁇ + 90 degrees 145 degrees from the horizontal
• the electrodes 26 of the first diffraction device 20 are oriented perpendicular to the electrodes 26 of the second diffraction device 20 '. In such an arrangement of the electrodes 26 on the respective substrates of the diffraction devices 20, 20 ', the
• Electrodes 26 are contacted on all four sides of the respective substrate.
• FIGS. 13 to 15 each show a part of a diffraction device 20.
• the diffraction device 20 shown in FIG. 13 is in an inactive state for displaying image contents, in FIG where the electric field lines 66 are aligned in a central region between the two substrates substantially parallel to the surface of the substrates.
• adjacent electrodes of a substrate with respective electrical voltages of different sign (+ or - indicated) are applied, so that the electric field lines 66 from a positively charged electrode 26 to the two adjacent negatively charged electrodes 26 -. and not to the oppositely disposed electrode 26 of the other substrate - run.
• the material (not shown) arranged between the two substrates can very quickly be converted into a defined neutral state, from which the material is returned to an active state, in which another diffraction structure is realized.
• a circuit shown in FIG. 14 could also be provided for the electrodes, according to which the electrodes of the two substrates are subjected to a substantially wedge-shaped voltage curve. Both the electrodes of the first and the electrodes of the second substrate are in this case subjected to electrical voltage of the same polarity. This could be realized by applying a predeterminable voltage (indicated by "1+”) to the electrode marked on the far left, and to the electrodes adjacent thereto on the right in each case a slightly higher predetermined additional voltage (indicated by "2 +", ..
• FIG. 15 shows a further exemplary embodiment of a wiring of the electrodes 26 of the diffraction device 20 in an inactive state for the image display.
• the electrodes 26 of the diffraction device 20 are connected in such a way that an electric field distribution results which prepares the refractive index distribution ⁇ (x) (shown in dotted lines) to be generated next.
• the electrodes 26 arranged there are each subjected to a predefinable positive voltage, so that at these points - even in the inactive state - a corresponding Refractive index distribution is prepared.
• the remaining electrodes 26 are acted upon by a predeterminable negative voltage.
• a predefinable diffraction structure or refractive index distribution can be set very quickly for the next active state, which allows a high refresh rate.
• FIG. 16 shows an exemplary embodiment of a voltage curve as a function of time with which an electrode 26 of the diffraction device 20 can be acted upon. Accordingly, at least one electrode 26 of the diffraction device 20 in time with each one initially increased electrical voltage U 0 applied, as this is initially required for adjusting the refractive index distribution to be generated. The electrical voltage is then adjusted in each case to a value Us, which is required for setting the refractive index distribution to be generated. As a result, another diffraction structure can also be adjusted very quickly in an advantageous manner.
• FIG. 20 shows, in a schematic representation, a light modulator 12 which has pixels 181 (enlarged in size) with red color filters, pixels 182 with green color filters and pixels 183 with blue color filters.
• FIG. 20A shows that at a point in time (or for a time interval t1) the light modulator 12 is exposed to a light wave field 161 of a red wavelength, for example to laser light having a wavelength of 635 nm.
• the pixels 181 of the red color filter light modulator 12 modulate this light according to the information written in these pixels 181.
• the green or blue color filter pixels 182, 183 block this light due to their color filters, regardless of the information written in these pixels 182, 183.
• a diffraction structure is written by means of the control device 14, which diffracts the light of the red wavelength and thereby directs it in the direction of an observer 50.
• FIG. 20B shows that at one point in time (or for another time interval t2), the light modulator 12 is acted upon by another light wave field 162, namely with light of a green wavelength.
• Pixels 182 of the green color filter light modulator 12 modulate this light according to the information written in these pixels.
• the pixels 181 and 183 with red or blue color filters block this
• a different diffraction structure is written by means of the control device 14, which diffracts the light of the green wavelength and directs in the same direction of the observer 50.
• a third wavelength field of blue wavelength is correspondingly applied to the light modulator 12.
• the pixels 183 of the light modulator 12 with blue color filter modulate this light according to the information written in these pixels.
• the red or green color filter pixels 181 and 182 block this light.
• a turn other diffraction structure is written, which diffracts the light of the blue wavelength and directs in the same direction of the observer 50.
• FIG. 20 thus shows an embodiment with a light modulator 12 with color filters 181, 182, 183 with a time sequential illumination.
• the diffraction device 20 arranged downstream of the light modulator 12 in the light propagation direction is in this case controlled such that a diffraction structure is in each case inscribed therein which is adapted to the respective illumination situation, that is to say for the light having the respective wavelength.
• FIG. 21 shows an exemplary embodiment in which the light modulator 12 is driven by the control device 14 at a lower image refresh rate and the diffraction device 20 is driven at a higher frame rate compared to the light modulator 12.
• the same information written in the light modulator 12 is successively diffracted by means of the diffraction device 20 and the field lens 40 to the left or right viewer's eye (eg 50 ', 50 ") of several observers, into the pixels 18 of the light modulator 12 by means of the control device 14
• Two viewers with left viewer eyes 50 'and 50 "as well as right viewer eyes 52' and 52" are in different positions in front of the diffraction device 20 and the light modulator 12.
• the light modulator 12 is provided with a light wave field 16 applied.
• FIG. 21A shows that at a point in time (or for a time interval t1), a diffraction structure is inscribed into the diffraction device 20 by means of the control device 14, which diffracts this light and thereby directs it in the direction of the viewer's left eye 50 'of the first observer.
• FIG. 21B shows that at another point in time (or for a different time interval t2), while the same information remains inscribed in the light modulator 12, another diffraction structure, which diffracts the light, is inscribed into the diffraction device 20 by means of the control device 14 directs it to the left viewer's eye 50 "of the second viewer.
• the position of the observer's eyes 50 ', 50 ", 52', 52" relative to the light modulator 12 can be detected, for example, with a position detection system.
• the position detection system can be designed such that it also provides the information as to how many observers are in the tracking range of the diffraction device 20.
• the refresh rate at which information is written into the light modulator 12 is independent of the number of viewers detected in this embodiment.
• the refresh rate at which a diffraction structure is written into the diffraction device 20 by the control device 14 can be adjusted up to a predefinable upper limit to the number of currently detected viewers, the upper limit being dependent on the properties of the diffraction device 20 and not on the properties of the light modulator 12 depend.
• FIG. 21 shows a system with a single diffraction device 20.
• This arrangement can also be configured analogously for the combinations of a plurality of diffraction devices, for example for two crossed diffraction devices (not shown in FIG. 21), of which a diffraction device uses light in a time interval t1 horizontal and the other diffraction device to the vertical position of a left viewer eye bends.
• the use of only one diffraction device is but sufficient in a system in which, for example, a vertically scattering means is included and tracking of the observer position must therefore be made only in the horizontal direction.
• FIG. 21 shows an example in which both observers are located at substantially the same distance D from the light modulator 12.
• FIG. 22 shows a light modulator 12 and a diffraction device 20 with two observers with left viewer eyes 50 'and 50 ".
• the information written into the light modulator 12 is detected by the diffraction device in a time interval t 20 bent so that it is directed substantially simultaneously to the left viewer eyes 50 'and 50 "of both observers.
• each pixel 18 of the light modulator 12 is associated with two different spatial regions of the diffraction device 20, which are e.g. each have half the width of a pixel in the vertical direction.
• a diffraction structure is written, which deflects light to the viewer's eye 50 'of a viewer.
• a diffraction structure is written which directs light to the viewer's eye 50 "of the other observer
• information is written in the light modulator 12 in a time interval only for the left or the right observer eye and in the diffraction device 20, spatial multiplexing with respect to the direction of deflection to the left or right viewer eyes 50 ', 50 "of the two viewers takes place.
• N different spatial regions of the diffraction device 20 can each be assigned to a pixel 18 of the light modulator 12. Then, each one of the N spatial areas of the diffraction device 20 directs light to a left or right viewer eye of the N viewer.
• FIG. 23 shows, in a further exemplary embodiment, a light modulator 12 and a diffraction device 20 with a viewer with left viewer's eye 50 'and right viewer's eye 52'.
• the information for the right observer eye 52 'and in other pixels 185 the information for the left observer eye 50' is inscribed.
• these pixels 184, 185 are each assigned spatial regions of the diffraction device 20, into which different diffraction structures are written, which bend the light in such a way that it is directed to the respective viewer's eye 50 'or 52'.
• information is thus written into the light modulator 12 for both observer eyes in a time interval.

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